NORTH DAKOTA GEOLOGICAL SURVE Y Wiisan M. Laird, State Geologist
BULLETIN 51
NORTH DAKOTA STATE WATER COMMISSION
Milo W. Hoisveen, State Engineer
COUNTY GROUND WATER STUDIES 12
Geology and Ground Water Resources
of
WELLS COUNTY Part 1-Geology
by
John P. Binemie, George A. Falgle, Ronald J. Bred and John R. Reid
Prepared by the North Dakota Geological Surve y in cooperation with the North Dakota State Water Commission, the United States Geological Survey , and the Wells County Board of Commissioners.
1967 This is one of a series of county reports pub- lished cooperatively by the North Dakota Geologi- cal Survey and the North Dakota State Water Commission . The reports are in three parts; Part I describes the geology, Part II presents ground water basic data, and Part III describes th e ground water resources. Parts II and III will be published later and will be distributed as soon as possible.
II Contents
Page ABSTRACT
INTRODUCTION 1 Purpose 1 Methods of Study 1 Previous Work 2 Geography 4
PRE-PLEISTOCENE STRATIGRAPHY 4 General 4 Cretaceous Rocks 4 Pierre Formation 4 Fox Hills Formation 4 Hell Creek Formation 5
PLEISTOCENE STRATIGRAPHY 5 Glacial History Prior to Deposition of the Surface Drift 5 Glacial Phases and Associated Landforms 6 Streeter Phase 10 History 10 Streeter drift 1 1 Glacial landforms 14 End moraine 14 Dead-ice moraine 15 Linear disintegration ridges 16 Circular disintegration ridges 16 Collapsed lake topography 1 7 Elevated lake plains 1 7 Collapsed outwash 17 Kames 17 Proglacial landforms 18 Postglacial landforms 18 Grace City Phase 18 History 18 Grace City drift 19 Glacial landforms 1 9 Overridden end moraines 19 III Page Ground moraine 23 Eskers and disintegration ridges 25 Kames 26 Proglacial landforms 27 Outwash plains 27 Meltwater trenches 27 Postglacial landforms 30 Lake plains 30 Windblown sand and silt 30 Heimdal-Martin Phase 30 History 30 Heimdal drift 3 1 Martin drift 3 1 Glacial landforms 3 1 Heimdal end moraine 31 Martin end moraine 32 Ground moraine 32 Eskers 32 Proglacial landforms 32 Meltwater trench 32 Lake plains 33 Analysis of the Surficial Drift 33 Analysis of Till Grain Size 33 Analysis of Boulders on the Surface 34 Analysis of Pebbles in the Till 34
ECONOMIC GEOLOGY 34 Sand and Gravel 34 Ground Water 35 Surface Water 35 Soil ------36 Petroleum 36
REFERENCES CITED 37
Iv
Illustrations
(plates are in pocket )
Plate 1 . Geologic map of Wells County . 2. Topographic map of the bedrock sTlface of Wells County showing bedrock subcrop pattern beneath the glacial drift. 3. Geologic cross-sections of Wells, County, North Dakota .
Figure 1 . Index map — 2 2. Diagrammatic cross-section of Wells 3 3. Stratigraphic column of Wells County G 4. Advance of the Wisconsinan ice 7 5. Cutting of tbeHeinudaltrench 0 6. Deposition of the Carrington Aquifer 9 7. Map of Wells County showing the areas directly affected byeach glacial phase l0 8. -Formation of the Streeter end moraine 1 1 9. Photograph of dead-ice moraine 15 10. Photograph of ice-thrust deformation 1 6 11. Early Grace City phase -_.__—_...._--_.--_.._ 20 12. Intermediate Grace City phase 21 13. Pony Gulch phase 22 14. Photograph mfesker 26 15. Sheyenne River meltwater trench 28 16. Terrace along the Sheyenne River meltwater trench 29
Table 1 . Average sand-silt-clay ratio of surface tills in Well s County —___ - . Surface pebble composition of Wells County tills 34
v Abstract
Wells County is in east-central North Dakota on the easter n flank of the Williston Basin. It is underlain by 4000 to 6000 feet of Paleozoic and Mesozoic rocks that dip gently to the west . The upper- most Cretaceous rocks, the Hell Creek, Fox Hills and Pierr e Formations, lie directly beneath the glacial drift ; isolated exposure s of the Fox Hills and Pierre rocks occur in the Sheyenne Rive r valley. Glacial drift covers the entire area averaging about 10 0 feet thick . In certain buried valleys it is more than 400 feet thick . The northern two-thirds of Wells County lies within the Drif t Prairie. This area is characterized by a surface of flat to gentl y rolling topography that is rugged on the end moraines and subdue d on the ground moraine and outwash plains . Associated with thes e major landforms are numerous washboard moraines, meltwate r trenches, and ice disintegration ridges . The southern third of Wells County is part of the Missouri Coteau, and is characterized by a hilly surface on dead-ice moraine. Associated with the dead-ic e moraine are numerous kames, lake plains and areas of collapsed outwash topography . Surficial deposits throughout the county ar e chiefly till and outwash, but proglacial and postglacial lake sedi- ments, colluvium, dune sand and recent alluvium are also present . As the late Wisconsinan glacier in east-central North Dakota thinned and receded, a large portion of it on the Missouri Cotea u stagnated and very slowly melted, resulting in hummocky area s of dead-ice moraine . The part of the glacier on the Drift Prairi e that remained active was increasingly affected by topographic high s over which it flowed . This resulted in lobation of the ice an d deposition of several end moraines from different directions . When a part of the glacier in north-central Wells County stagnated as a result of this lobation, it was dissected by streams that deposite d numerous ice-contact ridges . The most important economic resources in Wells County ar e the soil, ground and surface water, sand and gravel . Although no commercial oil production has yet been found, conditions necessar y for stratigraphic traps exist and further exploratory drilling ma y prove successful .
VI Geology and Ground Water Resource s of Wells County, North Dakota
by
John P. Blnemle, George A . Faigle, Ronald J. Rresl, and John R. Reid
INTRODUCTIO N Purpose This report is a descriptive and interpretive analysis of th e geology of Wells County, an area of 1300 square miles in centra l North Dakota in Tps . 145-150 N., and Rs. 68-73 W. (fig. 1) . It is one of a series of county reports conducted by the North Dakot a Geological Survey in cooperation with the North Dakota State Water Commission and the United States Geological Survey . Reports on the ground water basic data and hydrology of the area will be published separately. Primary objectives of this study were : 1) to provide an ac- curate map of the geology of Wells County ; 2) to arrive at a n understanding of the processes that shaped that geology ; 3) to examine the relationship of the glacial geology to ground wate r conditions; and 4) to determine the location and extent of grave l and other resources of the area . Methods of Study :During the 1963 field season, R . J. Kresl and G . A. Faigle, then graduate students at the University of North Dakota, mappe d the geology of Wells County for their Master of Science degre e theses. They traversed all section-line roads by automobile notin g the composition of sediments in road cuts and hand-augered holes . Data were plotted on county road maps and United States Geo- logical Survey maps of the 7 1/2 minute topographic series, scal e 1: 24,000. Aerial photograph stereopairs, scale 1 : 63,360, were availabl e for the county. Numerous samples of till and fossiliferous sediment s were collected by Faigle and Kresl for later laboratory analysis . Boulder, cobble and pebble composition analyses were made i n the field. Colors of sediments were determined by comparison with the ]Rock Color Chart (Goddard and others, 1951) . :During November of 1966, the senior author made a field chec k of Faigle's and Kresl's maps and made necessary corrections so the maps would conform to the standards of the North Dakot a 1 Geological Survey. Some areas were completely remapped ; in other areas only minor changes were needed . Previous Work The most comprehensive study now available on the Pleistocen e geology of North Dakota is by Lemke and others (1965) . Clayton (1966) has added to and revised this . Lemke and Colton (1958 ) summarized North Dakota Pleistocene geology and later publishe d their Preliminary Glacial Map of North Dakota (Colton, Lemk e and Lindvall, 1963) . Other studies include those by Branch (1947) , Easker (1.949) , and Tetrick (1949) , of the glacial geology of three
S. Dak .S
A' Montana North Dakota A' Minnesot a Quaternary-glacial drift S . L .
-500 0
-10000
Figure 1 . Index map . Shows the location of Wells County and the physiographi c subdivisions of the surrounding area . The cross-section of the area i s generalized to show regional relationships . 2
B-1364 C-66 9 D- 121 1 16-147-7 3 31-147-7 1 6-146-6 1 elev 1941 ele . 1702 elev 16 0 a--MISSOURI COTE-AU OR I PRAIRIE
TOP OF NIOBRARA FM
CRETACEOUS ROCKS SEALEVEL '_ — M TOP OF GREENHORN F . ._ — .— _ .~
TOP OF MOWRS FM _
TOP OF FALL RIVER-LAKOTA INTERVAL
- - TOP OF PIPER LIMESTONE - - - JURASSIC ROCKS — — fifteen-minute quadrangles that include part of northern Wells County. Filaseta (1946) investigated the ground water of the Fessen- den area. Several geologic reports of the present county series ar e now available for the area near Wells County ; they include: Kidder County (Rau and others, 1962) ; Stutsman County (Winters, 1963) ; Burlieigh County (Kume and Hansen, 1965) ; and Eddy and Foster Counties (Bluemle, 1965) . A comprehensive study of the Paleozoi c bedrock of eastern North Dakota (Ballard, 1963) includes the area covered in the present report . Several circulars describing sample s from exploratory oil wells have been published and various genera l studies of North Dakota bedrock have included all or parts o f Wells County. Geography Wells County has a short cool summer with a 117-day growin g season and 17 inches of annual precipitation, most of which fall s during the summer . This dry-subhumid climate is best suited for the production of small grains although some livestock is raised . Most of the county's population of 9231 is engaged in agriculture or agriculture-related industry . The largest town in the county is Harvey with a population of 2365. Fessenden, the county seat, ha s a population of 920 .
PRE-PLEISTOCENE STRATIGRAPH Y General Approximately 4100 to 6000 feet of Paleozoic and Mesozoic rock s lie on the Precambrian basement in Wells County (figs . 2 and 3) . Beneath the glacial drift of Wells County three Cretaceous formation s sub crop (pl . 2) . These are the shale of the Pierre Formation which subcrops in the eastern part of the county and the Fox Hills an d Hell Creek Formations which subcrop further west and southwest . Wells County is located near the eastern edge of the Willisto n Basin, so all the bedrock formations have a westerly regional di p and are thicker to the northwest . In this report only the bedroc k that subcrops beneath the drift will be discussed . Cretaceous Rocks Pierre Formation—The Pierre shale crops out in northeaster n Wells County along the walls of the Sheyenne River valley . Where weathered, the shale flakes and chips along distinct but discon- tinuous bedding planes. It is light gray and loose when dry, darker gray and cohesive due to included bentonite when wet. Some ben- ton:itic zones have a popcorn-like surface when dry and contai n yellow to buff streaks. Limonite stains are common on fracture s and small iron concretions occur in abundance . Fox Hills Formation—The Fox Hills Formation overlies th e Pierre Formation shale in the central and western parts of Wells County. It outcrops in several places along the Sheyenne River nea r 4 Harvey and in a roadcut in the northwestern corner of the county . The Fox Hills Formation consists of greenish-gray to yellow, fine and medium-grained sandstones interbedded with gray siltstones . It weathers to a miniature badlands topography in the exposure s south of Harvey ; this is typical of the uppermost sandstone membe r of the Fox Hills . Hell Creek Formation—The Hell Creek Formation overlies th e Fox Hills Formation in southwestern Wells County where it was penetrated by at least one test hole. It is the youngest pre-Pleistocen e formation in the county . The Hell Creek Formation is composed of a light gray, fine-grained siltstone that is moderately wel l cemented by a bentonitic clay . Dark mineral grains impart a "salt- and pepper" appearance to the siltstone .
PLEISTOCENE STRATIGRAPH Y
Glacial History Prior to Deposition of the Surface Drif t Most of the information about the glacial history of Wells Count y before the surface drift was deposited was obtained from test hol e logs . One phase of this history was the advance of the glacier tha t was responsible for the formation of the now buried Heimdal trenc h which contains the most important single aquifer in the county . As the ice advanced southward, it blocked the north-flowing drainag e of the area diverting it to more southerly routes . The most importan t of the north-flowing drainages were the Knife and Cannonball river s which flowed from southwestern North Dakota . Northeast of th e Missouri River the valleys are buried by glacial drift . In the Well s County area, these two rivers joined with meltwater from the glacier forming proglacial lakes in the valleys (fig . 4) . When the lake s overflowed the valley walls, a series of ice marginal trenches wa s cut ; the most important of these in the Wells County area is th e buried Heirndal trench . It formed along the ice margin in northern Wells County and eastward into Eddy, Foster and Griggs Counties (fig . 5) . After the ice advanced across this trench, it formed an outwas h plain in T . 147 N., R . 68 W. of Wells County and eastward into northwestern Foster County (fig . 6) . This outwash plain, now th e buried Carrington aquifer, was bounded on the southwest by a bed - rock high that extended from northeast of Sykeston to southwes t of Carrington . The northern and eastern boundaries of the outwas h plain must have been the glacier margin . Plate 2 is a map of the bedrock pattern beneath the drift . I t shows the subcrop pattern of the Pierre, Fox Hills and Hell Cree k Formations and the topographic configuration of the bedrock surface . Plate 3 shows several cross-sections drawn through the drift . Both of these plates are based on data secured from the North Dakot a State Water Commission and the United States Geological Survey. 5 Glacial Phases and Associated Landform s All the major landforms in Wells County are the result of glacia l activity ; they formed during the recession of the late Wisconsina n ice front from the area. South of North Dakota the glacier that ha d crossed the area consisted of two lobes, the James and Des Moines . By the time the ice margin had receded as far as central Nort h Dakota, these lobes had probably lost their identities . Two succeed- ing lobes, the Leeds and Souris lobes developed from the receding
Thicknes s in fee t (from to p Dominan t Systems Rock Units of named Lithology formation to top o f next lowe r formation )
Tertiary Pleistocene 0-500 Glacial drif t
Cretaceous Hell Creek Formation 0-50 Siltston e Fox Hills Formation 0-250 Siltston e Pierre Formation 550-1100 Shal e Niobrara Formation 450-500 Shal e Greenhorn Formation 200-300 Shal e Mowry-Newcastle Formations 200-250 Sandston e Fall River-Lakota Formations 100-200 Sandston e
Jurassic Unnamed Interval 50-300 Shal e Piper Formation 50-150 Limeston e
Triassic Spearfish Formation 0-80 Siltston e
Mississippian Madison Formation Poplar Interval 0-40 Dolomit e Ratcliffe Interval 0-80 Limeston e Frobisher-Alida Interval 0-210 Limeston e Tilston Interval 30-150 Limestone Bottineau Interval 490-570 Limestone & shal e Carrington Facies of the Bottineau 0-90 Shal e
Devonian Birdbear Formation 0-60 Limeston e Duperow Formation 80-170 Dolomit e Souris River Formation 170-250 Limeston e Dawson Bay Formation 20-90 Dolomit e Prairie Formation 10-50 Dolomit e Winnipegosis Formation 0-80 Shale
Silurian Interlake Formation 20-220 Dolomit e
Stonewall Formation 60-80 Dolomit e
Stony Mountain Formation 130-150 Dolomit e Red River Formation 580-620 Limeston e Winnipeg Formation 190-210 Shal e
Deadwood Formation 30-210 Sandstone & Cambrian Dolomite
Precambrian Igneous an d metamorphi c rocks
Figure 3 . Stratigraphic column of Wells County. 6 ADVANCIN G PROGLACIAL LAK E GLACIAL ICE
Figure 4 . Advance of the Wisconsinan ice . Proglacial lakes have formed in th e Knife valley and its tributary valley . Water flowing through the Can- nonball River system is unaffected at this time .
James lobe when the Turtle Mountains on the North Dakot a Canadian border changed the flow direction of the ice which ha d become too thin to override them . It is possible to construct a sequential history of ice recessio n over Wells County and adjacent areas . For purposes of discussion , 7 it is convenient to single out ice phases that occurred while th e glacier margin was receding through Wells County . Figure 7 show s the areas affected by each of these phases . In general, each of the glacial phases discussed here is character- ized by an end moraine with associated ground moraine and out - wash plains. The most important exception to this generalizatio n
Pierce Benso n
HEIMDAL TRENC H
II I \ \ L o
U 1 _
Wells _Co. Kidder Co. "Stutsman Co.
ADVANCING alowilaoftorl PROGLACIAL LAK E GLACIAL ICE
Figure 5 . Cutting of the Heimdal trench . Meltwater and water of the Knife an d Cannonball drainage systems have overflowed the preglacial valleys , cutting an ice-marginal trench through northern Wells and Eddy Coun- ties.
8 ADVANCING PROGLACIAL LAKE GLACIAL ICE
OUTWASH PLAIN (CARRINGTON AQUIFER )
Figure 6. Deposition of the Carrington aquifer . The ice here has advanced ove r the Heimdal trench and the dammed meltwater is flowing eastwar d between the ice and the bedrock upland on the south, depositing out- wash that was later to be covered by till . This outwash is now th e buried Carrington aquifer . the shaded area above . 9
is the Streeter phase which resulted in wide areas of glacial stag - nation on the Missouri Coteau . Developed on the major landform s are smaller features such as eskers, kames, disintegration ridge s and washboard moraines. Streeter Phas e History—During the Streeter phase, the edge of the active ic e that covered nearly all of Wells County was along the Wells-Kidde r county line (fig. 8) . The Streeter end moraine marks the edge o f the active ice that was responsible for the enormous amounts o f outwash sand and gravel in central Kidder County . Although glacia l ice still existed west of the active Streeter ice front, it had alread y stagnated and was covered by a layer of debris that served t o insulate the underlying ice and prevent rapid melting . For a mor e thorough discussion of the origin of dead-ice moraine, see Clayto n (1962, p. 34-38) .
1~ \ (Martin oo / phase J~~os 6(.0 % Heimdal phase ° Me' cxti
r ',
---' Gr
Figure 7 . Map of Wells County showing the areas directly affected by eac h glacial phase .
10 Streeter drift—Drift of the Streeter phase covers about 30 pe r cent of Wells County, almost entirely in the southern part (fig . 7) .
x x r STAGNANT IC E END MORAIN E x x x IH MOSTLY DRIFT-COVERE D
DIRECTION OF ICE FLO W OUTWASH
,l MELTWATER FLO W ACTIVE ICE
Figure 8 . Formation of the Streeter end moraine . Water flowing from the melting' ice deposited broad areas of outwash sand and gravel in Kidder County to the south . 11 The drift consists of till of the Streeter end moraine and the dead- ice moraine north of it, as well as associated gravel of collapse d outwash and ice-contact ridges . It also includes deposits of lake sediments within the dead-ice moraine . The Streeter drift was name d by Lemke and Colton (1958, p . 49) for the town of Streeter in southwest Stutsman County . The Streeter drift is the oldest surface drift in Wells County . It was deposited from ice that stagnated on the Missouri Coteau . The Streeter end moraine probably marks the last important activ e margin of the ice that flowed over the Missouri Coteau . It probably represents only a slight readvance of the Burnstad ice sheet an d the upper :Burnstad drift is probably only slightly older than th e Streeter drift. Radiocarbon dates from Streeter and Burnstad drifts in Logan , McIntosh, Stutsman and Kidder Counties range from 9000 to 11,650 years before the present (Clayton, 1962, p . 68) . Clayton concludes that the lower Streeter drift was deposited 11,650 ± 310 years ag o and the upper Burnstad drift was deposited continuously fro m slowly melting, stagnant glacial ice between 12,500 and 9,000 year s ago. This interval indicates that the stagnant glacial ice took abou t 3500 years to melt (Clayton, 1962, p . 68) . Fossil freshwater gastropod and pelecypod shells, ostracode carapaces and charophytes occur in several collapsed and elevate d lake deposits within the Streeter drift . They are as follows :
1. A lake clay beneath a collapsed lake deposit in the SE', sec. 6, T. 144 N., R. 68 W. 2. A lake clay beneath a collapsed lake deposit in th e SWI/, sec. 35, T. 145 N., R. 69 W. 3. A lake clay beneath an elevated lake plain 0 .1 mile east of the NW%, sec . 25, T. 145 N ., R. 71 W. 4. A lake clay beneath a collapsed lake deposit along th e east side of sec . 13, T. 145 N., R. 71 W. 5. A lake clay beneath an elevated lake plain in the NW I/ , sec. 14, T. 145 N., R. 70 W. 6. A lake clay beneath a collapsed lake deposit on the east side of sec . 17, T . 145 N., R. 69 W. 7. Lake sediments beneath a collapsed lake deposit in th e NEI/, sec. 35, T . 146 N ., R. 71 W. 8. Lake sediments beneath a collapsed lake deposit on the east side of sec . 10, T. 146 N., R . 71 W. 9. A lake clay beneath a collapsed lake deposit in the NW I/, sec. 12, T. 146 N., R. 71 W. 10. A very fine sand with interbedded lake clays beneat h 12
an elevated, collapsed lake deposit in the SW1/, sec . 6, T. 146 N., R. 70 W. 11. A lake clay beneath an elevated lake plain in the NE% , sec. 29, T. 146 N., R . 70 W. 12. Lake sediments beneath a collapsed lake deposit in the NE1/, sec. 32, T. 147 N., R. 73 W. 13. Lake sediments beneath a collapsed lake deposit on the north side of sec. 17, T. 147 N., R. 73 W.
A composite list of the fossils identified from these deposits of ice-contact washed drift is as follows; the numbers represen t the sites each fossil was found at: Fresh-water snails Armiger crista (Linnaeus) — 2, 4, 7, 9, 12 1 3 Gyraulus parvus (Say) — all sites except 3, 6, and 1 1 Gyraulus sp. — all sites except 2, 9, 12, and 1 3 Helisoma anceps (Menke) — 1, 4 Lymnaea humilis (Say) — 5, 7, 8, 9, 12, 1 3 Lymnaea sp. — 2, 1 2 Physa sp. — 7, 9 Promenetus exacuous (Say)— 1 2 Succinea sp. — 1 5 Valvata lewisi Currier — 4, 6, 10 Valvata tricarinata (Say) — all except 9 and 1 1
Sphaerid clams Sphaerium sp. — 1 0 Piisidium sp. — 2, 4, 5, 7, 8, 9, 12
Ostracodes Candona candida (Muller) — 1 1 Candona nyensis Gutentag and Benson — 1 1 Candona parachioenais Staplin — 5 Candona renoensis Gutentag and Benson — 2 Candona sp. aff. C. subtriangularis Swain — 2, 5, 1 1 Cyclocypris forbesi Sharpe — 3, 5, 1 1 Cypridopsis vidua (Muller) — 2, 5 Cytherissa lacustris Sars — 2, 3, 1 1 Ilyocypris gibba (Ramdohr) — 5, 1 1 Limnocythere f riabilis Benson and McDonald — 3, 5, 1 1 Limnocythere sp. — 6
Stoneworts Chara spp . — 2, 5, 10, 1 1 The mollusk identifications are from Kresl (1964, p . 73-75) and 13 Faigle (1964, p. 71-74) . Dr. R . Green, Head of the Geology Division , Research Council of Alberta, identified the ostracodes . The oogonia and calcified stem fragments of the genus Chara are found at some of the fossil sites . Chara is a small bushy plan t that grows in clear waters of lakes and ponds ; it may also b e found in near-shore waters where there is a high influx of fres h water (Jones, 1956, p . 37) . Abundant vegetation was probably presen t near the shores of many of the lakes . Most of the area associated with the Streeter phase is dead-ic e moraine . Other landforms include end moraine, disintegration ridges, collapsed and elevated lake deposits, collapsed outwas h plains, kames, and meltwater trenches . Drainage is in the youthfu l stage and post-glacial erosion has been negligible except wher e headward erosion of gullies is now beginning to dissect the north - east slope of the Coteau .
GLACIAL LANDFORMS End moraine—End moraine is defined as a ridge of drift , chiefly till, with moderate to high local constructional relief an d either overall or internal linearity, or both . It is the result of glacia l deposition at the margin of an active glacier . Linearity, the pri- mary requisite for recognition of an end moraine may be reveale d by the presence of small lineations, such as hills, ridges or depres- sions or it may be revealed solely by the overall pattern . The Streeter end moraine consists of three segments tha t extend from section 31 to 36 of T . 145 N ., R . 73 W. ; from sectio n 24, T . 145 N ., R . 73 W . to section 32, T . 145 N., R . 72 W . ; and fro m section 30 to 35 of T . 145 N., R . 71 W . Rau (1962, p. 29) nam- ed the westernmost of these segments the West Woodhouse Lake Loop . and the easternmost segment the East Woodhouse Lake Loop . The central segment he called a bedrock high, but, although it doe s lie on the flank of a bedrock high, it apparently is not cored b y bedrock and should therefore be considered to be another loop . I n this report it will be referred to as the Middle Woodhouse Lake Loop . All three segments of the Streeter end moraine of Wells Count y lie on the southern border of the county and continue into Sherida n and Kidder Counties . The boundary of the West and Middle Wood - house Lake Loops is gradational with dead-ice moraine ; there i s no distinct change in relief . The outer edge of the West Woodhouse Lake Loop is about a mile south of Wells County in Kidder County . Here, the contact is prominent and lineations are evident on aeria l photographs . The end moraines are composed of a calcareous, stony , clay till that is yellowish-gray (5Y-7!2) when dry and moderat e olive-brown (5Y 4/4) when wet . Numerous boulders are concen- trated on the surface . The East Woodhouse Lake Loop extends about three miles int o Wells County from Kidder County . It is about one mile wide . The end moraine decreases from a prominent feature with 150 to 20 0 feet of relief to an indistinct feature on the northwest where i t
14 merges with dead-ice moraine . The composition of the end moraine is similar to that of the West and Middle Woodhouse Lake Loops . Dead-ice moraine—Dead-ice moraine results from the slow ablation of a large mass of stagnant ice which is veneered wit h glacial sediments . Shearing within the ice as it moves over a n obstruction such as the Missouri Coteau brings subglacial till u p into the glacier where subsequent ablation concentrates it on th e surface. Running water and mass wasting redistribute the surfac e debris into such features as outwash plains, lakes, and randomly - oriented mounds of till all resting on stagnant ice . Complete melting of the stagnant ice results in the collapse of the previously - formed features and the undulating topography of dead-ice morain e results . For a discussion of dead-ice moraine terminology and a summary of the modes of origin see Clayton (1962, p . 34-38) . Most of the Missouri Coteau in Wells County is characterize d by dead-ice moraine (fig . 9) . Relief on the dead-ice moraine aver - ages less than 40 feet in a mile, but in places it is greater than 15 0 feet in a mile . Drainage on the dead-ice moraine is non-integrate d and the surface consists of innumerable depressions with randoml y distributed hummocks . In areas of relatively low relief, immatur e drainage systems have begun to develop and some of this land i s under cultivation . The most prominent feature on the Missouri Coteau of Well s County is Hawks Nest, a topographic and bedrock high, 6 squar e miles in area, in the extreme southeast corner of the county . Hawk s Nest projects 300 to 400 feet above the surrounding terrain and i t is characterized by high-relief hummocks and circular disintegration
Figure 9. Photograph of dead-ice moraine . Section 2, T . 147 N . . R . 73 W. Phot o by George Faigle . 15
Figure 10. Photograph of ice-thrust deformation of glacial drift . Exposed in a road cut in the SW',, sec . 21 . T . 145 N ., R . 71 W . Photo by George Fa iglc.
ridges . It is overlain in places by sand and gravel deposits a s much as 40 feet thick . Generally, the till of the dead-ice moraine is calcareous, ston y and clayey, yellowish-gray (5Y 7/2) when dry and moderate olive - brown (5Y 4/4) when wet . Boulders are few too scarce on th e dead-ice moraine . Linear disintegration ridges—Disintegration ridges are linear t o circular accumulations of drift deposited in direct association wit h masses of stagnant ice . The sediments were deposited largely b y mass movement of superglacial drift into cracks in stagnant ic e or between isolated blocks of ice, or by unfrozen, saturated sediment s being squeezed up into the cracks or around the blocks by th e weight of the ice . Linear disintegration ridges are straight to recti- linear ridges of till and/or outwash sediments . Several well-developed disintegration ridges occur in the are a that was covered by the Streeter ice . An excellent example is th e one in section 21, T . 147 N ., R . 72 W . This ridge is 4000 feet long , 600 feet wide and 70 feet high and it is composed, at least in part , of poorly-stratified sand and gravel . A dense concentration of boulders exists on the surface . The feature has a 90 degree ben d in the middle . Two longer but less prominent disintegration ridges are foun d in sections 26, 35 and 36, T . 147 N ., R . 73 W . and sections 5 and 6, T . 146 N ., R . 73 W . These features also have rectilinear shapes . Circular disintegration ridge: Circular disintegration ridges are a characteristic landform of the lower relief dead-ice moraine i n Wells County. These ridges are 300 to 500 feet in diameter, less than five feet high and they are -composed of till . They can be observed on aerial photographs as rimmed depressions but they can seldom be detected on the ground . Circular disintegration ridges probably formed either by squeezing up of till around isolated block s of stagnant ice or by reversal of relief of sediments deposited in a depression in the stagnant ice . Collapsed lake topography—Collapsed lake topography result s when the sediments deposited in a superglacial lake are irregularl y lowered as the stagnant ice melts . Collapsed lake topography has a rolling appearance and a boulder-free surface . An area of collapse d lake topography of about 4 square miles occurs in sections 26-2 8 and 33-35, T . 145 N., R. 70 W. Its surface is flat to gently undulatin g and underlain by about 5 feet of very cohesive, non-fossiliferous clay. Isolated patches of till are common on the surface . A 31/2 square-mile area of partially collapsed lake sediments occurs i n sections 1, 2, 10, 11, and 12, T . 146 N ., R. 71 W. and sections 6 and 7, T. 146 N., R. 70 W. Relief there averages less than 20 feet in a square mile. Fossiliferous clays, silts, marls, and fine sands occur beneath the surface . Elevated lake plains—Elevated lake plains result from initia l deposition of sediments in ice-walled lakes . When the ice melts and the lake drains, the lake bottom that has been covered b y lake sediments becomes a topographic high. The surfaces of th e elevated lake plains in Wells County are level or gently undulating . They extend 5 to 15 feet above the surrounding dead-ice morain e and they lack surface pebbles and cobbles . Most of the Wells County elevated lake plains contain abundant Pleistocene fossils. The largest elevated lake plain in Wells County is about 3 squar e miles in area in sections 31, 32 and 33, T. 145 N., R. 69 W . (pl. 1) . Many of the lake plains are too small to include on the map of th e county. Collapsed outwash—Collapsed outwash results when sand an d gravel is deposited by meltwater on stagnant ice . When the ice melts, the outwash is irregularly lowered forming abundant kettle s and trenches and a generally very uneven surface . Collapsed out- wash occurs in sections 6, 7, 17, 18, 19 and 30, T . 145 N., R . 73 W. Kames--Clayton (1962, p. 40) restricts kames in areas of dead- ice moraine to conspicuous hills of sand and gravel that are more prominent than the surrounding hills . Kames fitting Clayton's defi- nition are found in the NE%, sec . 7, T. 145 N., R . 72 W. ; NW%/ sec. 22, T. 145 N ., R . 73 W., and the SWI/, sec. 31, T. 146 N., R. 72 W. At this last location, the internal structure of the kame is exposed i n a sand and gravel excavation . All the layers dip away from a central high point.
17 PROGLACIAL LANDFORMS Proulacial landforms such as outwash, meltwater trenches, an d lake sediments are scarce and do not significantly affect the topog- raphy of the Missouri Coteau in Wells County . Several small melt - water trenches trend northward off the Coteau escarpment, how - ever. One heads in section 11, T. 145 N., R. 70 W ., one in section 26, T. 145 N., R . 68 W. and another enters the county in section 32, T. 145 N., R. 68 W . and trends northward . These meltwater trenche s probably drained the buried stagnant ice on the Coteau after th e active ice margin had retreated to somewhere north of th e escarpment . Extensive deposits of outwash, although absent in thi s part of Wells County . occur south of the Streeter end moraine i n Kidder, Logan and Sheridan Counties .
POSTGLACIAL LANDFORMS Lakes and sloughs are very numerous and their abundance i s typical of dead-ice moraine areas . The lakes and sloughs occup y low spots in the irregular topography . Those lakes and slough s floored by impermeable clay till contain saline water, the leve l of which fluctuates with changes in the rates of evaporation an d precipitation . Other lakes and sloughs underlain by stratified san d and gravel, contain fresh water and have a more stable level . These represent the intersection of a depression with the tru e water table.
Grace City Phase History—Withdrawal of the active ice front from the positio n it had occupied when it deposited the Streeter end moraine resulte d in stagnation of much of the ice on the Coteau in Wells Count y (fig . 111 . Some active ice remained on lower parts of the Coteau , but if this ice deposited any end moraines they later collapse d when the underlying stagnant ice melted . Lineations (pl . 1) mar k the ice borders shown on the Coteau in figure 11 . During this par t of the Grace City phase, the Grace City end moraine was deposite d in Foster and Stutsman Counties . On figure 12, the margin of the ice is shown shortly after i t had deposited the Grace City end moraine . Although some active ice is still shown on the Coteau, most of it by this time was limite d to the areas north of the Coteau . The lobe of active ice still on th e Coteau supplied meltwater to several lakes in the dead-ice moraine . These lakes drained through a now collapsed meltwater channe l at the margin of the small ice lobe . Meltwater from the activ e ice north of the Coteau became dammed in places and overflowe d scutheastward between the edge of the ice and the front of th e Coteau resulting in kame terraces and deep meltwater channel s along the edge of the Coteau . On figure 13, the active ice is shown at a still later stage . At about this time the Pony Gulch end moraine was deposited . Else- 18
where in the county, meltwater from the receding glacier flowed through an intricate network of channels to the southeast . In central Wells County, much of the meltwater flowed along the margin of the ice and many of the channels mark the former positions o f the ice as it receded from that area . Grace City drift—Drift of the Grace City phase covers abou t 45 per cent of Wells County . Its southern boundary coincides with the Missouri Coteau escarpment and its northern boundary wit h the southern limit of the Heimdal-Martin drift . The drift consists of till of the ground moraine that extends through central Wells Count y as well as associated gravel of the outwash plains south of Fessenden and the many ice-contact ridges . The name "Grace City" was firs t applied to the Grace City end moraine by Lemke and Colto n (1958, fig. 5) and the Grace City drift was defined in Eddy and Foster Counties (Bluemle, 1965, p . 24) as the drift associated with the Grace City end moraine which is named for the town of Grac e City in north-central Foster County . The Grace City drift was deposited after active ice was n o longer present on the Coteau . It resulted from an ice flow fro m the northwest, probably the Souris River ice lobe, that came into existence as a result of thinning of the ice in the vicinity of the Turtle Mountains (Lemke, 1958, p . 51) . It should be pointed out that the actual forward flow of the ice was continuous ; no re- advance is implied, only a change in flow-direction . The Grace City ground moraine is truncated in northern Wells and Eddy Countie s by the Heimdal end moraine which was deposited from the nort h by ice flowing around the west side of Sully's Hill . Only one radiocarbon date (W-1369) has been taken from the Grace City drift but, because sampling procedures were inadequate , this date ;should be disregarded . Several years elapsed from the time the wood was discovered until it was dated and all informatio n concerning its discovery is hearsay . Most of the area associated with the Grace City phase is groun d moraine. Four small end moraines, three of which were apparentl y overridden by the Grace City ice, are present in the area . Other landforms include eskers, kames, lake plains, washboard moraines , meltwater channels, outwash plains and terraces along the Shey- enne River.
GLACIAL LANDFORM S Overridden end moraines—An 8-mile-long segment of overridde n end moraine occurs from about 2 miles northwest of Sykeston t o 6 miles southeast. Although its arcuate shape implies deposition from the northeast, surface lineations indicate that southeast-flowing ic e may have overridden it . Another possibility is that the feature first developed along the edge of the receding .Grace City glacier . The end moraine is separated from the dead-ice moraine of the Missour i Coteau by a meltwater trench ; elsewhere it merges With Grac e City ground moraine . Local relief averages between 20 40 feet-
19
X X
X x x x x
X x x x x x x x x x x x x X x x x X
x X x x x x Foster C o
x x x .JJ U0 X X X x x x x x x x X x x X X x x X x X x x .• .
M END MORAINE ACTIVE IC E
• X X X STAGNANT IC E E GROUND MORAIN x x x MOSTLY DRIFT-COVERE D
OUTWASH DIRECTION OF ICE-FLOW
Ar- MELTWATER FLO W
LAKE MELTWATER TRENCH
Figure II . Early Grace City phase . During this phase the Grace City end morain e was formed in Stutsman and Foster Counties . In Wells County som e active ice still remained on the Coteau .
20
x x x \I/ x x x x 0 x x x x x :< x x x x x x x ; /' yy ~ x x x x x x x x x x x x x x x x x / / C (\ sr- X X X X x x x x x x x x x x x x x x x x ~ ..~ ~ .~~ x x x < x x x x x x x x x x xx x x x x x X X X x x x x x Xe> X x x x x x x I k``\ X X X x 6;;' Wells Co.x I x x ` .o x x ?~ ` x Stutsman Co . x X r X X X X X X X x X X~ X X X X X X X x~c n x x x x x x x x x x x x x x x x • 'K ' •• : X X X X X X X x X X X X X `A X X X X X X x x x x x X x x xl x x x . x x X X X X X X X X X X X k x X X
END MORAIN E ACTIVE IC E
X X X STAGNANT IC E GROUND MORAIN E X X X MOSTLY DRIFT-COVERE D
OUT WAS H DIRECTION OF ICE-FLO W
MELT WATER FLO W
LAKE_ MELTWATER TRENC H
Figure 12 . Intermediate Grace City phase . During this phase small end moraine s were deposited at the edge of tit- Coteau and meltwater that flowe d hetwt ea the ice-front and the edge •a the Coteau cut deep trenches .
21
END MORAIN E ACTIVE IC E
x x x STAGNANT IC E GROUND MORAIN E x x x MOSTLY DRIFT COVERE D
OUTWAS H DIRECTION OF ICE-FLO W
a-- MELTWATER FLO W LAKE MELTWATER TRENC H
Figure 13 . Pony Gulch phase . When the ice margin was in the position show n here, the Pony Gulch end moraine formed . Meltwater flowed from th e ice depositing thin, but extensive deposits of sand and gravel in th e areas shown . 22 in a mile, considerably more than on the ground moraine to th e northeast, but less than on the nearby dead-ice moraine . The till on the surface of the overridden end moraine is sandy, much like that of the adjacent ground moraine . Another small overridden end moraine is located between 8 and 11 miles southwest of Fessenden in T . 147 N., R. 71 W. (pl. 1) . Again, the overall shape suggests deposition from the northeast and the streamlined surface indicates the end moraine has been overridden by southeast-flowing Grace City or older ice but it i s likely the end moraine first formed at the margin of the Grac e City ice (fig. 12) . Local relief is low but the ridges rise more tha n 60 feet above the surrounding ground moraine and merge with dead- ice moraine on the southeast . The till on the overridden end morain e seems to be siltier than typical Grace City till . About 5 miles northeast of Harvey in northern Wells Count y and extending into Pierce County is a third end moraine tha t appears to have been overridden by south-flowing ice . This small loop of overridden end moraine is as much as 150 feet higher tha n the surrounding terrain ; its most conspicuous prominence is th e Butte De Morale in sections 2, 3, 10 and 11, T. 150 N., R.72 W. Sev- eral individual hills of the end moraine show strong northwest-south- east linearity but the overall loop-like shape of the feature indicate s it must have been deposited by a small south-flowing ice lobe . Anothe r possible interpretation of this feature is that it represents a till - veneered bedrock high. The till of this feature is indistinguishabl e from that of the nearby ground moraine except for the fact that windblown deposits from adjacent outwash make the surface mor e sandy . A 0.5 to 0 .8 mile wide, 50- to 70-foot-high ridge extends fro m section 25, T. 149 N ., R. 73 W. to section 20, T . 148 N., R . 73 W. Out- wash deposits of sand and gravel exist on the down-glacier side o f the ridge (pl. 1) so it seems likely the ridge is a segment of end moraine deposited by the receding Grace City ice sheet . Washboard moraines behind the ridge and parallel to it tend to confirm thi s conclusion. The ridge is composed of clayey till and the surface i s covered by numerous boulders . Ground moraine—Ground moraine is a gently undulating ac - cumulation of drift, chiefly till, with low local constructional relief , generally less than 50 feet in a square mile . Material in ground moraine includes drift that has been directly influenced by the base of the moving glacier (lodgement till) and drift that has been low- ered from upon and within the melting ice (ablation till) . The ground moraine associated with the Grace City phase i s characterized by smooth topography, gentle slopes and relief aver - aging between 5 and 20 feet in a square mile . Poorly-drained depressions occur but they are not as numerous as in the dead-ic e moraine of the Streeter phase . The highest elevations are at th e base of the Missouri Coteau near Heaton at about 1750 feet an d 4 miles southeast of Harvey at about 1700 feet . The lowest elevation s of about 1550 feet are at the eastern edge of the county .
23 Abundant washboard moraines occur on the Grace City groun d moraine . These are arcuate ridges of till, some of which are forme d by the shearing action of active ice over relatively inactive ice . Subglacial debris is brought to the surface of the ice and deposite d as ice-cored ridges (Bishop, 1957) . Some of the washboard moraine s may be formed simply as recessional features at the margin o f the ice and may thus be annual deposits . Washboard moraines ar e particularly abundant in the Fessenden and Manfred areas (pl . 1) . Their average width is about 20 feet, their height 5 to 15 feet an d their length up to 4030 feet . They are spaced at distances up to 2700 feet apart but 600 feet is the average distance between them . They are difficult to recognize without aerial photographs . Because washboard moraines commonly form normal to the direction of ic e flow, they are useful in determining the direction and possibly th e rate of retreat of the ice lobe that formed these features (Gwynne , 1942, p. 200) . Gravenor and Kupsch (1959, p . 55) regard the preser- vation of the washboard moraines as the result of stagnation of th e glacier ice . This is substantiated by ice disintegration features tha t are superimposed on the ridges in Wells County. Numerous eskers that probably formed in a stagnant or nearly stagnant ice sheet , cross the washboard moraines . Regardless of how they were formed , the abundant washboard moraines on the Grace City groun d moraine leave no doubt of the generally southeasterly flow of th e latest ice over the area . An elliptical-shaped topographic high referred to here as Eg g Lake Hill, is found in sections 14 and 15, T. 149 N ., R . 72 W . over about a half-square-mile area . It is about 4000 feet long, 2000 fee t wide, and 75 feet high . Some gravel is exposed in a roadcut on th e northern edge of Egg Lake Hill, but clayey till is the principa l sediment at the surface . Associated with the hill is a deep kettl e occupied by Egg Lake at an elevation more than 200 feet belo w the crest of Egg Lake Hill . This situation is nearly identical t o several features on the Heimdal end moraine of Eddy County ; that is, deep kettles located immediately on the upglacier side o f high hills . Perhaps Egg Lake Hill and similar hills in northwes t Eddy County, were formed when the ice scooped material fro m one area and dumped it a few thousand feet away . The till of the ground moraine is calcareous, silty to clayey , yellowish gray (5Y 7/2) when dry and moderate olive-brow n (5Y 4/4) when wet . Boulders and cobbles are absent to scarce at the surface. Some exposures of till in the NE 14, sec . 32, T . 149 N ., R. 68 W. and in the west half of sec . 21, T . 149 N ., R. 69 W. re- veal a horizontal fissile structure similar to stratification that sug- gests lodgement till . It contains highly decomposed granitic pebble s and is more compact than the massive till that comprises most o f the ground moraine . Although this till may be lodgement till, i t seems equally possible it is a till older than the surficial Grac e City drift that is simply not covered so deeply in that area . This would explain both the unusual compactness and highly weathere d aspect of the deposit .
24 Eskers and disintegration ridges—Numerous eskers and disinte- gration ridges occur over much of the Grace City drift of Well s County . Eskers are sinuous ridges, sometimes several miles long but commonly discontinuous, and they sometimes follow valleys . They normally have irregular crests with few surface boulders an d are composed chiefly of washed drift, with gravel most common. Till disintegration ridges are rectilinear, circular, or arcuate deposit s of drift, chiefly till, which form in depressions between blocks o f stagnant glacier ice . They can form through mass movement fro m above when material on the ice slides into the depressions or they may form by squeezing from below . The unusual abundance of eskers and disintegration ridges indicates the Grace City ice probably stagnated over a large are a of Wells County . Meltwater flowing through cracks, trenches an d possibly tunnels in the stagnant ice deposited the many ridge s now found on the till plain (pl . 1) . Many of these ridges contain a t least some stratified deposits, but only till was found in others . Although it is impractical to discuss all of the ridges in this report , some of the more interesting should be emphasized . The longest ridge in the county extends about 12 miles east from a point 3 miles north of Fessenden . This segmented, 20- t o 25-foot-high ridge lies almost entirely within the valley of the Jame s River and contains gravel in many places . Its top is flat, 75 t o 150 feet wide and covered by till and boulders . Its overall aspec t resembles the "tunnel valleys" described by Wright (1964, p . 4-5) although it is not clear whether it formed in a similar manner . A feature in Foster County much like this ridge is described b y Bluemle (1965, p . 27) but its origin is also obscure . A 9-mile-long gravel ridge is transected by the Sheyenne River about 3 miles northeast of Harvey' (pl . 1) . This 5- to 20-foot-hig h ridge is paralleled in places by a valley that may have formed at the same time. On its northwest end the ridge becomes burie d by sand and gravel deposited by Martin ice meltwater. Gravel was found in the only pit on the ridge . A complex of gravel-cored ridges occurs in a zone beginning 4 miles northwest of Fessenden and extending to Heaton . Most of the individual ridges are less than 2 miles long and most of the m are located in a narrow band of outwash that marks the edge o f the stagnant Grace City ice at a late stage of its existence . At a pi t in one of the ridges (SW 1/4 , sec . 32, T. 148 N ., R . 70 W.) a soil profil e developed on gravel is overlain by stratified sand, gravel and wind - blown sand . The elevation of the buried soil is below the surroundin g land surface so it may have developed prior to the deposition o f the overlying ridge . A 40-foot-high ridge in section 35, T . 149 N ., R . 72 W. and sec- tions 3, 4 and 10, T. 148 N., R . 72 W. is up to 1250 feet wide and cor- ed with sand and gravel . Exposed in a pit in the SE'%, sec . 35, T. 149 N., R . 72 W., is a buried 3-foot-thick soil profile that is developed on gravel typical of the ridge . The soil is overlain by 1 to 5 feet of stratified gravel with till in places, especially on top of the overlyin g 25 gravel . Some chunks of soil are included in the overlying till . This soi l is elevated above the surrounding terrain and most difficult t o account for . Its A horizon thickness of 3 feet presumably indicate s an extended interval of time, perhaps several hundred years ma y have been required to develop it . A 6-mile-long esker occurs in sections 11 and 13, T . 149 N ., R. 70 W. and sections 17-22, T. 149 N ., R . 69 W . (fig . 14) . This esker is 10 to 20 feet high, 250 feet wide and is contained in a valley . I t is composed of fine, clean sand and capped by 3 to 5 feet of highl y compacted clayey till . The present interpretation is that this situatio n does not necessarily imply overriding . Saturated till probably sli d from the ice onto the ridge as it formed . Kames--Kames, as defined by Holmes (1947, p . 248) are "mounds composed chiefly of gravel or sand . whose form has re- sulted from original deposition modified by any slumping incident to later melting of glacial ice against or upon which the deposi t accumulated ." The kames of Wells County fit this description .
Figure 14 . Photograph of esker . View is east-southeast from 0 .5 miles east of th e northwest corner of Section 13, T . 149 N ., R . 70 W . Photo by Ron Kresl .
An 80-foot-high hill 2 miles south of Sykeston that contains a t least some gravel is probably a kame . This kame is part of a smal l end moraine (p . 21) and may have been overridden by the Grac e City ice . It is capped by till and is slightly elongate toward th e south . A group of 3 gravel hills in section 24, T . 149 N ., R . 73 W . ar e about 30 to 40 feet high and associated with a complex of eskers and terraces along the Sheyenne River (pl . 1) .
26 PROGLACIAL LANDFORMS Outwash plains—Outwash is washed and stratified drift deposited by meltwater flowing in streams beyond a glacier margin ; an outwash plain is a broad unit of outwash . A small outwash plain south of Fessenden (pl . 1) is underlai n by thin gravel and sand with intervening areas of till. Its elevation is higher than the ground moraine to the northeast, so the Grac e City ice must have bordered it there . Relief on the outwash plai n is generally less than 10 feet in a mile. Some sand and gravel is also present to the east, but it is less continuous and not show n on the map . The southwest boundary of the outwash is marked b y a rise in the land surface that can be traced as a sort of lo w "escarpment" all the way from the vicinity of Sykeston to nea r Harvey (pl . 1) . A larger cutwash plain occurs north of Bowdon adjacent to th e Missouri Coteau (pl . 1) . This outwash, also discontinuous, may hav e been derived in part from meltwater flowing from the Missour i Coteau but most of it was probably derived from the Grace Cit y ice. Its surface is covered by post glacial alluvial fans in places . Because elevations on the outwash plain are variable, it is difficul t to determine in which direction the meltwater flowed, although on the northeastern-most part of the plain it must have flowed south - east, parallel to the adjacent Grace City ice . The outwash is probably slightly older than that near Fessenden, as the ice had not ye t retreated that far . Generally, the gravel of this outwash plain i s of poor qua':ity with considerable clay and scattered areas of lami- nated silts that indicate the presence of ponded water . In sections 27, 34 and 35, T . 148 N ., R. 73 W., is a lake plain having rathe r indefinite boundaries . Lake sediments are present elsewhere, bu t it was impossible to define their limits . The largest outwash plain in the county is in the Harvey are a and it is quite complex . Two levels are associated with the plain ; the upper, older level was deposited by the Martin meltwater an d the lower, younger level by water from later glacial activity i n counties to the northwest of Wells County . The higher part of th e outwash plain slopes from an elevation of about 1625 feet at th e edge of the. Martin end moraine to about 1600 feet southeast of Harvey. The lower part is confined mostly to broad trenches an d terraces along the Sheyenne River and is mostly slightly lowe r than 1600 feet in elevation except along the James River where it is a little higher . In places it is difficult to distinguish the tw o levels because they have been modified by recent erosion and win d deposition. The lithologies are about the same beneath both levels , that is, coarsely stratified sand and gravel . Meltwater trenches—In Wells County, water flowed from th e margin of the melting glacier through a complex system of melt- water trenches. Because the regional slope is northeastward, th e meltwater tended to flow that way but, due to the presence of the Grace City glacier, it was diverted southeastward along the margi n 27 of the ice. Therefore, many of the meltwater trenches were originally formed as ice-marginal channels . When the ice front retreated north - westward, 1:he water flowing in these southeast-trending trenches was free to flow northeastward again, parallel to the regional slope. Because the ice wasted only gradually, the meltwater once agai n became diverted by the ice and formed a new ice-marginal trenc h further to the northeast. Most of the meltwater trenches of Wells County have only smal l amounts of associated outwash sediments. At least one trench, th e James valley north of Fessenden, contains an associated esker . Wright (1964, p . 5) , suggested that trenches of this type may hav e beer. eroded by water under hydrostatic pressure flowing beneat h the ice . When the overlying ice ablated, the superglacial drift ma y have been lowered or washed into the trench partially filling it an d burying the outwash sediments that might have been present . Th e till bottoms of some of the trenches may have resulted in this way . The several meltwater trenches of Wells County include th e Sheyenne River valley, the James River valley, the Heimdal di - version trench, and the valleys of Pipestem and Little Pipeste m Creeks. There are also innumerable smaller trenches . The largest meltwater trench in the county is the one that no w carries the Sheyenne River (fig . 15) . The terraces on the walls o f the trench, especially well-developed in the Harvey area, are about 40 feet above the present floor of the valley (fig . 16) . The elevation s on the terraces decrease from about 1600 feet south of Harvey t o about 1573 feet southeast of Wellsburg . They probably are parts
Fig-tire 15 . Sheyenne River meltwater trench . View is north in section 24, T . 149 N ., R . 73 W . Photo by George Faigle .
28 Figure 16. Terrace along the Sheyenne River meltwater trench. NWsec . 13 , T . 150 N ., R . 71 W . Photo by George Faigle .
of the floor of an ancestral trench that formed about the sam e time as the lower of the two outwash plains in the Harvey area . The original stream that flowed at the elevation of these terrace s was probably continuous with the Heimdal Diversion trench alon g the southern margin of the Heimdal end moraine . It was not unti l later, when water from the ice-marginal Souris and DeLacs River s was available, that the deeper trench was cut below the terraces . Considerable gravel is present at several locations on terrace s in the Sheyenne River meltwater trench . Gravel is particularl y abundant in the NW l/4 , sec. 13, T . 150 N ., R. 71 W, on one of th e terraces . In the Heimdal Diversion trench considerable good grave l remains ; water from Glacial Lake Souris that cut the Sheyenn e River valley did not flow through the Heimdal Diversion trenc h and therefore did not remove the gravel there as it did in th e Sheyenne River valley . The James River meltwater trench follows a highly irregula r course through Wells County (pl . 1) . It has no significant associate d terraces and in most places it is floored with till; only insignifican t amounts of gravel are associated with it . The trench is generally less than 20 feet deep and from 1/8 to 3/ mile wide. Boulders ar e concentrated on the floor in some places, probably clue to remova l of the fine fraction by washing from the till . The Pipestem-Little Pipestem Creek meltwater trenches wer e originally formed es ice marginal trenches between the Grace Cit y ice and the front of the Missouri Coteau . A kame terrace wit h associated gravel deposits in sec . 36, T . 146 N ., R . 69 W ., and sec . 29 6, T. 145 N., R. 68 W. and sec. 1, T. 145 N., R. 69 W. was deposited by water that flowed in the trench during an early stage of it s existence. Considerable supplies of excellent gravel are associate d with parts of the meltwater trench system adjacent to the Cotea u escarpment .
POSTGLACIAL LANDFORM S Lake plains—West of Fessenden in the northeast part of T . 148 N., R. 71 W. is a 1 .5 square-mile area mapped as a recent lake de - posit . Two well-developed boulder pavements indicate a former shore - line in sections 12 and 13, T . 148 N., R. 71 W . The sediments in the basin are thin, discontinuous layers of light olive-green lake clays and silts (5Y 5/2, wet) with sand stringers . :Egg Lake (secs. 9 and 10, T . 149 N., R. 72 W .) is surrounded by a st:randline 20 feet higher than the present lake surface . Betwee n the two levels is a fine yellowish-gray sand (5Y 7/2, wet) on whic h a soil has developed indicating that the 20-foot drop in lake leve l may not be a recent event but possibly even one that occurre d soon after the retreat of the Grace City ice sheet . Windblown sand and silt—Deposits of windblown sand and sil t occur throughout Wells County, but they are of limited extent an d have not been mapped in detail . Heimdal-Martin Phase History--Although the exact relative ages of the Heimdal an d Martin end moraines and the landforms associated with them ar e not known, it is convenient to treat them as being penecontempo- raneous in Wells County . Further work in counties to the north , particularly Pierce and Benson, will be necessary to determine the relationships of the two end moraines . At some time prior to the deposition of the Heimdal and Marti n end moraines, a large part of the glacier in north-central Well s County stagnated (fig . 17) resulting in an area of thin stagnant ice that became riddled with innumerable eskers, disintegration ridges and asssociated meltwater channels . The presence of thes e innumerable ice-contact features is probably the best evidence fo r such a body of stagnant ice . Not nearly so many ridges would hav e been preserved if the ice had been active ; moving ice tends t o obliterate ice-contact features . Most of the larger of these ice- contact features are shown on plate 1 but many smaller ones ar e also present. As this stagnant ice wasted, the meltwater flowing along its margins and over its surface deposited widespread, but thin, accumulations of sand . Much of this sand was not mappe d because it is too thin and discontinuous . The Martin and Heimdal end moraines may represent a sligh t readvance of the ice. It is not known just where the active ice margin re-established itself when the large area of ice became stag- nant in north-central Wells County, but it was probably not a grea t distance north of the present Heimdal and Martin end moraines . 30
• y x x x x x x x x x L K X X X X X X X x x x ~ x x
x X '.K X X X~ 1VI X
X K X X X X 71 X X X X X X X X X X X X X X X X X X X X X X X X X X X x x x x x x X X x x x x x x x x X x { X X X ; . X X X X X x x X X X X -DX X X x 1'.. + q { X X X X x x X X x x %~ x « .X . .x . wens Co. : X '' x x ~Stutsman Co . xV o X x x x x x x x x ix x x x x x x x x X X — X X X x x x x x x x x x x rnX X X X X x x : x x x x x x x x x x x ?~ X X X X c. x x x pc x X x x X x x X x x x X X X X x :•::• : x x x r x x x x x x X X X A x x x x x :Kidder
END MORAIN E ACTIVE IC E
x x x STAGNANT IC E GROUND MORAINE x X X MOSTLY DRIFT-COVERE D
OUTWAS H DIRECTION OF ICE-FLO W MELTWATER FLO W
LAKE MELTWATER TRENC H
Figure 17 . 1feimdal-Martin phase . During this phase the Heimdal and Martin en d moraines were deposited . Abundant ice-contact features developed i n the area covered by stagnant ice in northern Wells County . 31 The primary factor influencing this shift in ice flow directions wa s probably a regional thinning of the glacier coupled with the presenc e of bedrock highs to the north, particularly the Turtle Mountains . When the glacier became too thin to override the Turtle Mountains , it split into two lobes, the Leeds on the east and the Souris on the west (Lemke, 1958, p. 51) . The Leeds ice deposited the Heimdal end moraine and the Souris ice deposited the Martin end moraine . The small loop of end moraine on the Wells County line betwee n the Heimdal and Martin end moraines has already been discussed . It is possible this end moraine is recessional and was deposited slightly before the Martin end moraine but because its surfac e appears to be streamlined it seems more likely it was deposite d much earlier, perhaps during the first advance of late Wisconsina n ice over the area . The position of the end moraine coincides wit h the ice margin along which the now buried Heimdal trench formed . The loop of end moraine may have formed at the same time th e trench was being cut, perhaps by meltwater from the same ice that deposited the end moraine . Heimdal drift—Drift of the Heimdal phase covers about 1 0 per cent of Wells County . It consists of the Heimdal end morain e and small amounts of associated ground moraine along with som e mirror meltwater trenches . The name "Heimdal" was first applie d to the Heimdal end moraine by Branch (1947, p . 6) for the village of Heimdal in northeast Wells County . Martin drift—Drift of the Martin phase covers about 15 per cen t of Wells County . It consists of the Martin end moraine and a large outwash plain in the northwestern part of the county . The name "Martin" was first applied to the Martin end moraine by Lemk e and Colton (1958, p . 49) for the village of Martin in northeas t Sheridan County.
GLACIAL LANDFORM S Heimdal end moraine—The Heimdal end moraine covers most of T . 150 N., Rs. 68 and 69 W. and about 30 per cent of R . 70 W. It ranges in width from 2 to 5 miles and extends northward into Benson County and eastward into Eddy County . The topography of the end moraine is variable, ranging from close-spaced ridges a s in secs . 13 and 24, T . 150 N., R. 69 W. to broad, flat sags as in secs . 10 and 15, T . 150 N., R . 68 W. Local relief averages from 40 to 80 feet in a square mile, but up to 150 feet near Black Hammer Hil l in ,section 8, T. 150 N., R . 68 W. Boulders and cobbles are abundant on the Heimdal end moraine . The drift of the end moraine consists mostly of clayey an d sandy till that ranges in color from dark yellowish-brown (10YR 4/2 ) to moderate olive-brown (5Y 4/4) . Much of the till is loose and fissile with decomposed granitic pebbles . The lineations on the end moraine seem to outline two loop-lik e segments, one on either side of Black Hammer Hill which form s an apex around which the lineations are grouped . This may mean
32 that Black Hammer Hill is a bedrock high that split the ice int o two small lobes, but no test hole data are available to either confir m or deny the existence of a bedrock high here . Martin end moraine—The Martin end moraine crosses the ex- treme northwest corner of Wells County . It is a very extensiv e feature, shown by Lemke, Colton and Lindvall (1963) to exten d from the Turtle Mountains on the northeast to somewhere west o f Minot on the west . The Martin end moraine marks a recessiona l phase of the Souris ice lobe which flowed southeastward betwee n the Turtle Mountains and the Missouri Coteau. In Wells County the Martin end moraine is a prominent range of hills with local relief of about 50 feet in a square mile . The till comprising the end moraine is clayey, calcareous, and yellowish - gray (5Y 7/2, dry) to light olive-brown (5Y 5/6, wet) . Consider- able amounts of associated sand and gravel occur sporadically a s well as near small meltwater channels in the end moraine . Boulders and cobbles are abundant on the surface . Ground moraine—The small areas of ground moraine located north of the Heimdal end moraine have an average relief of 1 5 to 20 feet in a square mile, but some hills rise as high as 40 fee t above surrounding areas . The topography is characterized by rounded hills that appear to be streamlined suggesting that ice overrode them at one time . Washboard moraines indicate that th e ice receded northward . The till of the ground moraine is silty an d light olive-gray (5Y 5/2) to dark yellowish-brown (10Y 4/2) . Boulders and cobbles are numerous on the surface. ;Eskers--Two small ridges that may be eskers are located i n secs. 5 and 6, T. 150 N., R . 73 W. They are closely associated wit h a meltwater trench; one rises from the trench floor . A pit in one of the eskers contains boulders up to 3 feet in diameter along wit h chunks of fine, cross-bedded sand that must have been froze n when they were deposited there .
PROGLACIAL LANDFORMS Meltwater trench—The Sheyenne River valley extends throug h the northeast corner of Wells County . It is flanked by prominent gravel and sand terraces that occur at an elevation of 1480 feet , approximately 60 feet above the floor of the valley. These terraces correspond to the Grandfield terraces discussed by Bluemle (1965 , p. 62) . They are unrelated to the terraces along the Sheyenne Rive r near Harvey because they are at least 100 feet lower in elevation . Further work needs to be done on the North Fork of the Sheyenne River in Benson and Pierce Counties to the northwest before th e drainage history can be adequately explained . An excellent southeast-trending meltwater trench is located i n secs . 5, 6 and 8, T. 153 N., R. 73 W. It is about 1,600 feet wide, 1 5 feet deep and it contains large amounts of sand and gravel . The trench connects with the outwash plain in front of the Martin en d moraine .
33 Lake plains—Three feet of unfossiliferous, stratified lake silt s overlie fine sand on the 1480-foot terrace of the Sheyenne valley i n the NE1%, sec . 11, T. 150 N ., R. 68 W. Two feet of gravel overlie the lake sediments. Similar lake sediments were found in severa l locations along the Sheyenne valley in Eddy County . They were probably deposited during a temporary damming of the channel , perhaps as the result of a landslide somewhere downstream fro m the area . The lake sediments are always found at an elevation o f about 1480 feet .
ANALYSIS OF THE SURFICIAL DRIF T Analysis of Till Grain Size—Samples of till were taken from 14 4 localities in Wells County at depths of 3 to 4 feet beneath the sur- face. The percentages of sand, silt and clay were determined fo r each sample by sieving out the sand and gravel and analyzing th e remaining fraction with a hydrometer to determine the silt-cla y ratio . Gravel was considered to be anything over 840 microns in diameter (it would not pass a screen with openings of 840 microns) , sand included sediment between 63 and 840 microns, silt include d sediment between 4 and 63 microns and clay included everythin g smaller than 4 microns in diameter . Table 1 shows the averag e of the clay, silt, and sand for each of the drifts studied . TABLE 1
SAND % SILT % CLAY %
STREETER TIL L 29 38 3 3 44 samples
GRACE CITY TIL L 39 36 2 5 91 samples
HEIMDAL TILL 26 46 28 9 samples
Average sand-silt-clay ratio of surface tills in Wells County The slightly higher clay percentage in the Streeter till and th e slightly higher sand percentage in the Grace City till may reflec t the bedrock over which the ice sheets moved. The Streeter drift was deposited by ice that came from the northeast and therefor e moved over Pierre shale bedrock whereas the Grace City drift wa s deposited by ice that came from the northwest, moving over Fo x Hills and Hell Creek sandstones . The Pierre shale probably sup - plied the larger clay fraction to the Streeter drift, and the Fo x Hills and Hell Creek formations the larger sand fraction to th e Grace City till . There is, however, a wide divergence in size ratios and the averages may not be a true representation of the actual size distribution . In Eddy and Foster Counties to the east, the size compositions of the Grace City and Heimdal drifts correspond re- markably well to the same drifts in Wells County . Additional samples from other counties need to be analyzed before it can be
34 determined whether there is a systematic particle size distinction among the various drifts .
Analysis of Boulders on the Surface—The percentages of the variou s lithologic types of boulders were determined at 27 locations in Wells County. Igneous rocks represented-well over 50 percent of the tota l boulders on each of the drift _sheets, but no real differences in the rock-type distribution were found for any particular part of th e county. Analysis of Pebbles in the Till—Table 2 shows the percentages of the three most common types of pebbles in till throughout Well s County. Samples of 100 pebbles each collected at 31 locations are grouped according to the drifts from which they were taken . The pebbles are grouped in Table 2 into igneous plus metamorphic peb- bles, carbonate pebbles and local bedrock, pebbles. Carbonate peb- bles include limestone and dolostone as well as chert which wa s probably derived from Paleozoic carbonate formations . Local bed- rock includes shale and sandstone .
TABLE 2
IGNEOUS AN D LOCA L METAMORPHIC % CARBONATE % BEDROCK %
STREETER TILL 50 1 2 7 samples 38
GRACE CITY TIL L 35 56 9 17 samples
HEIMDAL TIL L 42 49 1 0 6 samples
MARTIN TILL 70 29 1 1 sample
Surface pebble composition of Wells County till s
Although the Martin till has a higher igneous and metamorphic pebble concentration than the other tills, it should be pointed out that the Martin till was sampled at only one location . This is in- sufficient data to draw conclusions from . Carbonates are far more abundant in the pebble size than in the boulder size . This pre- sumably reflects a greater resistance on the part of the crystallin e rocks to mechanical disintegration as opposed to carbonates and other sedimentary types .
ECONOMIC GEOLOG Y Sand and Grave l Sand and gravel occur as ice-contact deposits, beneath river terraces, underlying outwash plains and as channel deposits . Some 35 deposits have been exploited for road construction material, bu t much more extensive deposits remain . The quality varies inversely with the shale content and the shale content is commonly high, s o the deposits have their economic limitations . The best sources of sand and gravel are the well-sorted sedi- ments of the terraces along the Sheyenne River valley, particularly in secs. 13 and 14, T . 150 N., R. 71 W. This terrace deposit is being mined but considerable supplies remain. Other potential source s are the eskers and some of the disintegration ridges throughout the county. In addition, several large kames on the Missouri Cotea u contain appreciable amounts of sand and gravel . Ground Water The ground water resources of Wells County will be discussed in detail in Parts II and III scheduled to follow this publication . For this reason, only a few general observations will be included here. Most of the water used by farmers in Wells County comes fro m gravel and sand aquifers within the glacial materials. Of particular importance are the deposits in the buried Heimdal trench in th e northern part of the county (pl . 3) . The buried gravel deposits in the preglacial Knife and Cannonball valleys and their tributaries may also contain important supplies of water . The Sheyenne River meltwater trench is underlain by deposits o f permeable gravel and sand that yield appreciable supplies of water . The town of Harvey obtains its water supply from these gravel s through a system of collection wells in sec . 21, T. 150 N ., R. 72 W. Similar collection wells placed elsewhere in the meltwater trench should also yield significant supplies of ground water . Other meltwater trenches such as those in which Rocky Ru n and the Little Pipestem Creek flow, may be underlain by water - bearing gravels . The town of Fessenden obtains its water from a well in the SE'%, NEi/4 , sec. 4, T . 149 N ., R . 70 W. The water is obtained from a sand and gravel aquifer at a depth of 150 feet . This aquifer may be related to the meltwater trench it underlies , or it may be in the Heimdal trench deposits . Most of the gravel s in the Heimdal aquifer lie at depths greater than 150 feet so prob- ably the Fessenden water supply comes from a source unrelated to these gravels . In addition to the above mentioned ground water sources, th e Carrington aquifer underlies part of eastern Wells County nea r Cathay in T . 148 N., R . 68 W. In general, any extensive surfac e deposit of sand and gravel should be investigated for its groun d water potential . The outwash plains in northwestern Wells Count y and along the front of the Coteau in T . 147 N., Rs . 71 and 72 W. may contain appreciable supplies of water . Surface Wate r All the streams in Wells County are ephemeral and would prob- ably contain very small amounts of surface water during most o f
36 the year were it not for the numerous small dams along th e streams. The ephemeral streams include the Sheyenne and Jame s Rivers, Rocky Run, Pipestem Creek and Little Pipestem Creek . No perennial lakes exist north of the Missouri Coteau in Wells Count y but there are numerous ones on the Coteau . These are mostly saline , however, due to their impervious till floors . Springs are common on the north face of the Missouri Coteau, especially near Hawks Nest in the southeast corner of the county . Some springs also occur along the valley walls of the Sheyenne River . Soil The entire area has soil of the Chernozem great soil group. The most common soil types are those associated with the Barne s and Svea soils. These soil types are formed in areas of end, dead- ice and ground moraine and reflect the general morphology of the county. They are black, silty loarns and clay loarns essentially un- leached of carbonates . Petroleum Sixteen wildcat wells have been drilled for oil in Wells County as of July 1, 1966. All the holes were dry. According to Ballard (1963, p . 38) the Carrington Shale facies provides two types of stratigraphic traps that are potential pro- ducers of petroleum. The first of these, the facies change of th e Bottineau carbonates in an updip direction into the Carrington Shal e occurs along a north-south line from western Wells County to centra l Emmons County. The other occurs in eastern Wells County and t o the south where the Carrington Shale seals the truncated Birdbea r and Duperow Formations . The Duperow Formation produces oil i n western North Dakota and the Birdbear has excellent porosity s o Wells County does have potential as a possible future petroleu m producer.
37 References Cited
Ballard, F . V., 1963, Structural and stratigraphic relationships in the Paleozoi c rocks of eastern North Dakota : North Dakota Geol . Survey Bull . 40, 42p. Bishop, B . C ., 1957, Shear moraines in the Thule area, northwest Greenland : U. S. Army Corps of Engineers, S .I.P .R .E . Research Report 17, 46 p. Foster Counties, North Dakota, pt. 1, geology : North Dakota Geol . Survey Bull. 44, 66 p. Bluemle, J . P., 1965, Geology and ground water resources of Eddy and Foste r Counties, North Dakota, pt . 1, geology : North Dakota Geol . Survey Bull . 44, 66 p. 1965b, Influence of bedrock highs on glaciation in east-central North Dakota : Geol . Soc. America (abstract), Program, 18th annual meeting , Rocky Mountain Section, p . 23 . Branch, J . R ., 1947, The geology of the Flora Quadrangle : North Dakota Geol. Survey Bull . 22, 35 p. Clayton, Lee, 1962, Glacial geology of Logan and McIntosh Counties, Nort h Dakota : North Dakota Geol . Survey Bull . 37, 84 p . 1966, Notes on Pleistocene stratigraphy of North Dakota : North Dakota Geol . Survey, Rept. of Inv . 44, 25 p . Colton, R . B ., Lemke, R . W., and Lindvall, R . M ., 1963 Preliminary glacial map of North Dakota : U . S . Geol . Survey, Misc. Geol . Inv. Map I-331 . Easker, D . G., 1949, The geology of the Tokio Quadrangle : North Dakota Geol. Survey Bull . 24, 35 p . Faigle, G. A ., 1964, Glacial geology of western Wells County, North Dakqta : Grand Forks, North Dakota Univ. (unpublished master's thesis), 85 p . Filaseta, Leonard, 1946, Ground water in the Fessenden area, Wells County , North Dakota : North Dakota Geol. Survey Ground Water Study no . 1 , 22 p. Goddard, E . N ., and o'hers, 1948, Rock-color chart : Nat . Research Council, 6 p . Gravenor, C . P ., and Kupsch, W . 0 ., 1959, Ice-desintegration features in western Canada: Jour . Geol ., v. 67, p . 48-64 . Gwynne, C . S., 1942, Swell and Swale topography of the Mankato lobe of the Wisconsin drift plain in Iowa : Jour. Geol ., v . 50, p . 200-208 . Holmes, C. D ., 1947, Kames : Am . Jour . Sci ., v. 245, p . 248 . Jones, D . J., 1956, Introduction on Microfossils : Harper and Bros ., New York, 406 p . Kresl, R. J., 1964, The geology of eastern Wells County, North Dakota : Grand Forks, North Dakota Univ. (unpublished master's thesis), 110 p. Kume, Jack, and Hansen, D . E., 1965, Geology and ground water resources o f Burleigh County, North Dakota, pt . 1, geology: North Dakota Geol . Survey Bull. 42, 111 p . Lemke, R . W ., and Colton, R . B ., 1958, Summary of Pleistocene geology of North Dakota, in Mid-Western Friends of the Pleistocene Guidebook 9t h Ann. Field Conf . : North Dakota Geol . Survey Misc . Ser . 10, p. 41-57 .
38 Lemke, R . W., Laird, W. M., Tipton, M . J., and Lindvall, R . M., 1965, Quaternary geology of northern Great Plains, in Wright, H . E., Jr. and Frey D . G., The Quaternary of the United States : Princeton, Princeton Universit y Press, p . 15-27 . Rau, J . L., Bakken, W . E., Chmelik, J . C., and Williams, B . J., 1962, Geology and ground water resources of Kidder County, North Dakota, pt . 1, geology : North Dakota Geol . Survey Bull . 36, 70 p. Tetrick, P . R ., 1949, Glacial geology of the Oberon Quadrangle : North Dakota Geol . Survey Bull. 23, 35 p . Thoriithwaite, C . W., 1948, An approach toward a rational classification of cl i mate : Geog. Rev., v. 38, p. 55-94 . Wills, B. L., 1963, North Dakota ; the northern prairie state : Ann Arbor, Edward Bros., Inc., 318 p. Winters, H. A., 1963, Geology and ground water resources of Sluisman County , North Dakota, pt . 1, geology : North Dakota Geol . Survey Bull . 41, 84 p . Wright, H. E., Jr., 1964, Wisconsin glaciation of Minnesota, in Midwest Friend s of the Pleistocene Guidebook 15th Ann . Field Conf . : Minnesota Geol . Survey, 32 p .
39